Scientists study the world to gather knowledge. Engineers utilize this knowledge to solve problems and create a better world. This blog is about using biological knowledge to engineer better gardens, more efficient systems, tastier foods, and, well, anything else I can think of.

Monday, February 15, 2016

There are many different kinds of mushrooms out there,
classified by their source of food. Parasitic mushrooms attack living
organisms. Mycorrhizal mushrooms form a symbiotic relationship with plants,
trading nutrients for sugar. But when it comes to the world of mushroom
cultivation, the real species of interest are the saprophytes, the mushrooms
that decompose dead tissue. But even those come in several different varieties.
There are primary, secondary, and tertiary decomposers. Tertiary decomposers
are mushrooms that live in soil, scraping out a living on the little scraps of
nutrition they can find here and there. Very few are of culinary significance.
Primary and secondary decomposers, on the other hand, are the species that
compose the majority of our culinary mushrooms.

When a tree falls in the forest, it is the primary
decomposers that move in and start the process of turning the body of the tree
back into soil. Think about the trunk of a tree. While the tree is alive, there
isn't much living inside the tree, besides the tree, of course. Plus, it is
made of solid wood (weird how that works, eh?) and most living creatures can't
penetrate through to get to the energy stored in the wood. Fungal species are
quite adept at it, though, and among the mushrooms, there is still lots of
competition for any new food source. Once the primary decomposer detects an
available food source, it throws all its energy towards occupying it. Growth is
very rapid and it grows a huge amount of tissue in a fairly dense
concentration.

Once it has colonized what it can grab, the primary
decomposer produces a flush of mushrooms, then proceeds to decompose as much of
the food source as it can.

Chunk of wood that has been fully decomposed by white rotfungus, still looks like wood

However, primary decomposers are not particularly
complete in how much they decompose. Most are either brown rot fungus, which
means they decompose the cellulose and leave the lignin behind, or white rot
fungus, which means they decompose the lignin and leave the cellulose behind. Either
way, the wood still looks pretty much like wood when the fungus is done with
it. It is just a whole lot softer and lighter.

The secondary decomposer moves in and picks up where the
primary decomposer left off. It certainly feeds on the cellulose and/or lignin
that is left over, but it also decomposes the other compounds present in the
tree.

The biggest difference between the two is the type of
environment they prefer to grow in. The primary decomposer is adapted to the
inside of a freshly fallen log. They prefer an environment with little to no
competition. They produce ideally on pasteurized sawdust, straw, or something
similar. Secondary decomposers are a little different. In nature, once the
primary decomposers have finished, insects, soil bacteria, and all kinds of
other organisms have started invading. It provides a richer micro-ecosystem.
This is the preferred habitat of the secondary decomposers. Some won't even
produce mushrooms in sterile substrate. Several even prefer a well-composted
substrate that still has some woody/fibrous components to it.

The same piece of wood as above, just squeezed to showhow soft it is. It is ready for a secondary decomposer

As for how to tell the difference, just look at the growing
requirements. If the mushroom will fruit off of just sawdust, vertical or
horizontal surface, it is probably a primary decomposer. If it requires a
casing layer and only fruits from a horizontal surface, it is probably a
secondary decomposer. Examples of primary decomposers are shiitake (Lentinula
edodes), oyster (both Pleurotus and Hypsizygus species), reishi (Grifola
frondosa), and pioppino/black poplar (Agrocybe aegerita). Examples of secondary
decomposers are button/portobello (Agaricus brunescens), king stropharia
(Stropharia rugoso-anulata), and shaggy mane (Coprinus comatus).

Considering my currentprojects, what are the implications
of this information? Well, the main thing is that when mixing mushrooms and
gardening, the information about what habitat the mushrooms like is very
important. So when you are doing it in aquaponics, like I am, there need to be
some minor adjustments to how you do it. For example, if you are doing
traditional aquaponics, using media, primary decomposers are going to be your
best bet. But rather than sawdust/woodchip blocks, which is the usual preferred
method, partially buried logs would be best. The worms would gobble up the
blocks too soon, whereas they would do no appreciable damage to the logs.

On the other hand, if you are doing aquaponics with soil,
both primary and secondary decomposers can be used. The primary decomposers
will still do better in logs, but the active soil in an aquaponics system can
be really beneficial for secondary decomposer mushrooms. Plus, they would add
additional filtration for the water.

A little over a year ago I created a woodchip bed in my
aquaponics system using king stropharia mushrooms. The results were better than
expected. They obviously thrived in that environment. I intend to keep
experimenting as often as I can manage. I think there are great combinations
out there yet to be discovered.

About Me

Disclaimer

I am not an expert on any of the topics presented here, merely an enthusiastic hobbyist. I claim no responsibility for how this information is used and make no guarantees that it is completely accurate, only accurate to the best of my knowledge.